2009 Infiniti QX56

MY 2009 INFINITI QX56 HAS A SERIOUS ISSUE WITH THE REAR SUSPENSION THAT STARTED ABOUT A YEAR AFTER I GOT THE CAR WHEN IT WAS AT ABOUT 100,000 MILES AND HAS GOTTEN WORSE, EVEN THOUGH REPAIR SHOPS AND DEALER KEEP TELLING ME IT'S 'FINE'... WHEN TRAVELING DOWN THE HIGHWAY AT SPEEDS OVER 50MPH, IF I HIT OR DRIVE OVER ANY BUMP OR POTHOLE OR DIP OR UNEVEN PAVEMENT, THE BACKEND OF THE CAR FEELS LIKE IT IS GOING TO FISHTAIL OR SWING OUT OF CONTROL AND HAS GOTTEN WORSE. NOW, AT SLOW SPEEDS WHEN I HIT ANY OF THE AFOREMENTIONED TYPICAL ROAD / PAVEMENT ISSUES, THE BACK END SOUNDS LIKE IT IS SLAMMING DOWN ON ITSELF. ALSO, THE BRAKES NOW SOMETIMES FEEL LIKE THE PEDAL IS "LOOSE" AND GOES NEARLY TO THE FLOOR. IF I PUMP THE BRAKE AGAIN, IT GOES BACK TO NORMAL. I HAVE TAKEN THE VEHICLE IN AND BEEN TOLD THE "BRAKES ARE JUST FINE" AND THEY ACT LIKE THEY DON'T KNOW WHAT I AM TALKING ABOUT. THE SAME WITH THE SUSPENSION, EXCEPT FOR NOW THERE IS A "TINGING" SOUND SOMETIMES UPON STARTING OR ACCELERATING. THE REPAIR SHOP TOLD ME THE STRUTS AND SHOCKS ETC 'ARE FINE', BUT THAT THERE MAY BE AN ISSUE WITH THE SUSPENSION THE DEALER ACTED LIKE THEY DIDN'T KNOW WHAT I WAS TALKING ABOUT, BUT AFTER RESEARCH HERE ... I SEE THAT THIS EXACT PROBLEM IS COMMON WITH THIS VEHICLE AND THE 2011, SUCH THAT THERE IS A RECALL FOR THE MODELS MANUFACTURED NOV. 2009 AND 2010. ALL OF THESE VEHICLES SHOULD BE FIXED BY MANUFACTURER. THEY KNOW THIS IS AN ISSUE AND EVEN RECALLED SOME VEHICLES. THIS TRULY COULD KILL US SOME DAY... BRAKES DON'T WORK OR THE CAR'S BACK-END SWINGS OUT OF THE LANE AND FISHTAILS OUT OF CONTROL ON THE INTERSTATE. IT HAPPENS ALL THE TIME NOW. I RESEARCHED BECAUSE I NEED TO DRIVE MY SON TO COLLEGE AND KNEW IT DIDN'T FEEL SAFE. I FOUND YOU MAY ALREADY BE INVESTIGATING THESE ISSUES AND I WOULD LIKE A RESOLUTION AND TO HAVE MY TESTIMONY INCLUDED. IT'S DANGEROUS.